He was born in 1564 and died in 1642. He made major contributions to physics and astronomy. He made improvements to the telescope, so he was able to see the planets in better detail. He found that Venus had phases similar to our moon. And he saw that Jupiter had its own moons.

The standard scientific view of that time was that everything orbited the earth. But Galileo's observations made him conclude that instead the SUN was the center of the solar system, not the earth.

But this was no ordinary scientific debate. Galileo's scientific ideas were considered a threat to the powers-that-be of the day. Because Galileo contradicted accepted science, he was persecuted. The pope wanted Galileo to keep quiet, but Galileo refused. He stood trial against the Inquisition, was found guilty of heresy, and spent the rest of his life under house arrest.

How was this man a threat to society - was he a violent man? No! He just had some differing scientific views. Oh, I guess I should mention - Galileo's science was right! And for telling the truth and making the established order look a little foolish, he paid the price.